Thrusters - Why way more common in performance surfing

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southsea
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Thrusters - Why way more common in performance surfing

Post by southsea »

Watching the WSL CT & QT series, unless the waves are monster and barreling 99.9% of the pros are on high-performance thrusters and it has been this way for years. On the PWA and AWT I would guess thrusters are still more popular but it's a much closer mix between tri & quads.

Why is competition surfing so uniformly tri but windsurfing is more of a mix bag?
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BTB
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Re: Thrusters - Why way more common in performance surfing

Post by BTB »

Dont know - but i much prefer a thruster set up as it just makes sense to me. And i cant stand the 5 box stick what you want in approach.

For fins to work they need un-interupted water flow. Put them to close together and you get the drag without the grip/lift. In addition, for any fins outside of the center line, the shaper will have to estimate the best toe in angle and that will always be a compromise as the faster the board moves the straighter the water flow. A center fin goes straight - there is no compromise and it works irrespective of board speed.

Maybe the appeal of quads is that they do slide out more and in that case its down to style and feel over efficiency. I wont pretend i'm a good enough sailor to make judgements on feel.
Jeroensurf
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Re: Thrusters - Why way more common in performance surfing

Post by Jeroensurf »

We have wider boards, way higher speeds, wider arcs so I can imagine that gives a different designbrief.
Personally I don,t really have a preference. I have 2 Witchcrafts that are really good, but also owned Goya and Quatro Quads and the silver mistral Twinzer that I really really liked. Different and good in different thingsd, but I can,t say that one was 100% better as the other. Besides the amount of fins different shapes too.
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BTB
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Re: Thrusters - Why way more common in performance surfing

Post by BTB »

Jeroensurf wrote: Wed Apr 07, 2021 12:43 pm We have wider boards, way higher speeds, wider arcs so I can imagine that gives a different designbrief.
Personally I don,t really have a preference. I have 2 Witchcrafts that are really good, but also owned Goya and Quatro Quads and the silver mistral Twinzer that I really really liked. Different and good in different thingsd, but I can,t say that one was 100% better as the other. Besides the amount of fins different shapes too.
I'm not sure that wave sailing involves higher speeds. Maybe recreational wave sailors in real world conditions do sail faster but the trend in maui is for smaller and smaller sails and just float out, don't jump and wave ride like a purist.
grantmac
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Re: Thrusters - Why way more common in performance surfing

Post by grantmac »

I have a board which performs better as a quad than a thruster. I mean better in every category and I've tried quite a few different fin configurations in both.

So I'd say there is more going on than simply how many fins it's got.
Jeroensurf
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Re: Thrusters - Why way more common in performance surfing

Post by Jeroensurf »

BTB wrote: Wed Apr 07, 2021 3:57 pm I'm not sure that wave sailing involves higher speeds. Maybe recreational wave sailors in real world conditions do sail faster but the trend in maui is for smaller and smaller sails and just float out, don't jump and wave ride like a purist.
That isnt a trend. ;)
I have been on Maui 8 ? years ago and sailed a lot at lower Kanaha and of course Hookipa+ Lanes when there was a bit of Kona.
At Kanaha you can sail like planing out, but the wave when it has some size and the speed of the wave creates soo much apparent wind that you need to sail smal , otherwise you are overpowered on the wave.
On Lanes and Hookipa (for those haven,t been there, the are like 300m away from each other) the waves are even faster so that effect is even bigger.
Because of the aparent wind we do go faster as surfers.
At Lanes I literately made a bottom turn around a surfer who was surfing the wave as well and wasn't aware of me (or ignored that I was way before him on the wave).

Maybe at the Northsea the differences are closer, although over here we use more sailpower, but also at Gwithian for example windsurfers are way faster as surfers.
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Manu
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Re: Thrusters - Why way more common in performance surfing

Post by Manu »

Because windsurfing boards work better as a single in most cases! Thruster is just a way to get a bit more grip from a short single. Quads (or secured twins) are looser for more forgiving and sharper turns. However, they are more technical over rough terrain. At least that's how I see things :) !
PK1111
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Re: Thrusters - Why way more common in performance surfing

Post by PK1111 »

Having surfed for 30 years, the tri fin works amazingly well and I’ve never felt the need for increased grip from a quad, or looseness of say a twin.
The surf board is powered by the wave and should mostly be banked on one side as turning, which keeps a side thruster loaded up.
The fins are relatively small as they only provide grip to stop the back of the board spinning out and convert lift into forward energy.

Adding a sail to the mix changes everything as the drive comes from the sail and not just the wave.
Windsurfers do travel at higher speeds for longer periods than surfers (typically 20 knots on a wave board), so fin set up is more compromised to support straight line sailing.
The fins tend to be bigger than surf fins and provide more lift, as well as grip.
When under powered or mostly straight line sailing, a single fin is still excellent.
For slightly more control, a tri fin reduces the lift and increases the grip.
For ultimate control, a quad set up works very well and with limited downsides.

I’m a believer in keeping fins as small as you can to get the job done.
Who knows, surfing may change fins again, (finless boards?) but for now, the thruster set up works great.
Jeroensurf
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Re: Thrusters - Why way more common in performance surfing

Post by Jeroensurf »

Manu wrote: Wed Apr 07, 2021 8:00 pm Because windsurfing boards work better as a single in most cases! Thruster is just a way to get a bit more grip from a short single. Quads (or secured twins) are looser for more forgiving and sharper turns. However, they are more technical over rough terrain. At least that's how I see things :) !
imo that is very much depending on how and where you are sailing.
In steep short waves like we have here in the netherlands I can make 2 wide and fast turns with a singlefin or 4/5 with a Tri or quad.

Thinking about shapes:
I have 4 sups, and the bigger wider ones are quads ( an Hypernut 7.10x31.5x130l + an 8.2x30x115l custom loosely based on a Hypernut tail with Airborne nose and pro rocker) while the smaller more performance shaped boards work better as a tri for me (Starboard pro8.5x29x112l and 8x28.5x105l custom).
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Bouke/Witchcraft
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Re: Thrusters - Why way more common in performance surfing

Post by Bouke/Witchcraft »

southsea wrote: Tue Apr 06, 2021 6:33 pm Watching the WSL CT & QT series, unless the waves are monster and barreling 99.9% of the pros are on high-performance thrusters and it has been this way for years. On the PWA and AWT I would guess thrusters are still more popular but it's a much closer mix between tri & quads.

Why is competition surfing so uniformly tri but windsurfing is more of a mix bag?
This was all discussed extensively on the boards forum.
In surfing, it is normal for the side fins to have toe-in. So they don´t drag and turn better and you can use bigger side fins (all 3 equal size). In windsuring many boards still do not have at all or not enough toe-in. So they have to keep the side fins small to not end up having too much drag and have too much straight lining effect. And to then still get enough fin area, they use quad fins or a trifin with a big centre fin which is far from a thruster like on surf boards. I use 3 fairly equal sized fins on my boards but for more control in big waves, you can put a bigger centre fin (I never do). We have also modified our pre twisted fins for trifin boards that don´t have toe-in like Quatro or Goya, For example changed the stock 11+19 cm fns for 13.5+14. Each time the customer was amazed how much difference this made: Earlier planing, higher top end speed, more speed and lot tighter turning on the wave.
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Here is more info: https://witchcraft.nu/boards/trifin/
There is some difference in speed on the wave between surfing and windsurfing but not that much. It depends a lot on the wave and wind orientation. This was last week on a 5.2 in 18 knots of cross off shore wind (especially in the last part where the wave wraps in a bit): https://www.facebook.com/bouke.becker/v ... 61103744/
Normally in 40 knots cross on shore you would not get that speed DTL. And surfers shooting out of a barrel do get a lot of speed. So it depends.
https://witchcraft.nu/. Boards, sails, masts, fins.
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